Is it possible to merge multiple labels into one label in a segmentation image?

Hi all,

I have an image with multiple labels and I want to merge them and label it as a single label. Is it possible for me to do it in 3D Slicer or ITK-SNAP?

Here is the image displaying in 3D Slicer and ITK-SNAP:

It seems a silly question but I am stuck in it and I didn’t find a solution after searching online for a long time. Much appreciated for your help!

Yes, you can do it in slicer simply.
If you just want get a model, you can merger them into one model in surfacetool.
And if you tend to get a label you can convert them as a segment and then have a booloperation to get a one segment and convert back to a label.
Good luck!